Recently, attention has been paid to such regenerative medical treatment that transplants cells built by using pluripotency of brain- or spine-derived neural stem cells or that of ES cells (embryonic stem cells).
Medical applications of the neural stem cells and the ES cells raise many problems such as immunological rejection in cell transplantation, ethical issues, and unbalance between demand and supply of transplant cell sources.
Accordingly, when it becomes possible to use, as a transplant source, cells derived from a transplant recipient per se, autotransplantation becomes possible, thus solving the foregoing problems.
An example of cells expected to serve as the transplant sources is iris pigmented epithelial cells of an eyeball.
Iris pigmented epithelial cells are a component of an iris serving as tissue for opening and narrowing a pupil in accordance with an amount of light so as to adjust an amount of light which reaches a retina.
The inventors of the present invention have reported in Non-Patent Document 1 (Experimental Cell Res. (1998) 245, 245-251) that the inventors have successfully isolated and cultured iris pigmented epithelial cells of a chick.
Furthermore, the inventors have made it possible to isolate and culture mammalian iris cells (from mouse, rat, or human embryo) by a method improved from the process of Non-Patent Document 1 (see Non-Patent Document 2: Nature Neuroscience (2001) 4 (12), 1163).
It is possible to collect part of iris pigmented epithelial cells from a patient per se. Therefore, if it becomes possible to produce tissue cells by using iris pigmented epithelial cells, regenerative medical treatment using cells of the patient per se will be realized. (To the best of the inventors' search, there is no document concerning a method according to the present invention for producing tissue cells from stem cells derived from iris pigmented epithelial cells of an animal, and tissue cells obtained by the method.)
However, no method for producing non-neural cells from iris pigmented epithelial cells of an animal has been established.
The present invention has been completed in consideration of the foregoing problems and has an object to provide a method for producing tissue cells derived from iris pigmented epithelial cells of an animal, and tissue cells obtained by the method, the method and the tissue cells making it possible to solve problems such as immunological rejection in cell transplantation, ethical issues, and unbalance between the demand and supply of transplant cell sources.